I suppose any film with roughly 30 speaking parts, and intended as the grand culmination of story arcs explored across 18 movies over the last 10 years is bound to feel a bit overstuffed. Avengers: Infinity War, directed by Anthony and Joe Russo, clocks in at a butt-numbing 2 hours and 29 minutes. I won’t lie, it does feel long. But it’s also very enjoyable for the bulk of it.

Remember how the end credits sequence in the first Iron Man movie, all the way back in 2008, hinted at the idea of an Avengers Initiative? Who’d have thought at the time that this is what it was leading up to! Because, as you probably know already, unless you’ve been living under a rock, Infinity War teams up practically everyone that’s ever appeared in the Marvel Cinematic Universe: the Founding Avengers – Iron Man, Thor, Captain America, Hulk, Black Widow; the Guardians of the Galaxy – all of them; later entrants Scarlett Witch, Vision, Doctor Strange, Spider-Man, Black Panther, and other characters from each of their respective worlds. Throw a stone and you’ll hit a superhero.

You’re also likely aware that only one thing could bring all these good guys together – a bad guy, namely Thanos, who’s been a looming threat referenced in previous Marvel films, and who is finally centrestage this time around. Played by Josh Brolin in a terrific motion-capture performance that doesn’t miss a nuance, Thanos is a 12-feet-tall, purple-skinned mega villain with an oversized chin, who’s bent on acquiring all six of the Infinity Stones, and wiping out half of the galaxy’s population to save the other half – don’t ask! Every superhero in the MCU, summoned from their respective stomping grounds, must do what they can to stop him.

That’s as far as I can tell you in terms of plot. Much of the joy in Infinity War comes from watching the awkward interactions and the unlikely friendships developed within this massive ensemble of do-gooders, many of whom don’t know each other, or even of each other’s existence. At one point Bruce Banner asks, very puzzled, “There’s an Ant-Man and a Spider-Man?” The script mines humour from personality clashes, conflicts, mild irritations, and one-upmanship. Let’s just say the combustible pairing of two sarcastic ego-maniacs Tony Stark and Doctor Strange delivers plenty laughs. Banner is having a hard time unleashing his inner Hulk, Peter Parker won’t shut up with all the pop-culture references, and Thor is thrown in with the wisecracking Guardians, led by the irrepressible Peter Quill.

But because there are so many of them in the mix, it’s practically impossible for every significant character to get a huge amount of screen-time here. Inevitably some get more to do than others. I was especially bummed to see one of my favourites, Scarlett Johansson’s Black Widow, criminally underutilised. Even a promising fight scene between four badass female characters is prematurely and abruptly cut off. Frankly the only fella who gets a chunk of cinematic real estate is Thanos. In addition to destroying everything in his path in pursuit of those coveted Infinity Stones, his complicated relationship with adopted daughters Gamora (Zoe Saldana) and Nebula (Karen Gillan) yields some surprisingly affecting moments.

It’s true also of other narrative strands. Infinity War has some well-earned and genuinely emotional moments involving characters you’ve had many years to be invested in. The action too never feels like a blur. Superhero films tend to climax in loud, messy CGI battles (both the previous Avengers films are guilty of this) that go on and on until the razor-sharp cutting makes your eyes glaze over and you can’t tell who’s doing what to whom. The action sequences in Infinity War – and there are plenty – never feel generic, perhaps because there are so many distinct superheroes and superpowers at play. The final stretch, in fact, is especially bold and somber, with the filmmakers raising the stakes in a way that these films seldom do.

There’s been a lot of chatter online about who lives and who dies at the end of this movie. Don’t expect any clues or any answers from me, but I will tell you that it’s hard to take everything that you see seriously, given that you know there’s a second movie out next year that’s meant to wrap up this arc. Still, you have to hand it to the Russos for the extent they’re willing to go to in order to deliver shock, suspense, and a mostly thrilling experience.

I’m going with three-and-a-half out of five for Avengers: Infinity War. It is overstuffed and overlong, but there’s so much going on you’ll barely notice. Best enjoyed with a big tub of popcorn.